Amoxicillin Dosing for Acute Otitis Media in a 13.43 kg Child
For a 13.43 kg child with acute otitis media, give amoxicillin 80-90 mg/kg/day divided into 2 doses, which equals approximately 600 mg twice daily (total daily dose: 1,075-1,209 mg/day). 1
Dosing Algorithm
Standard First-Line Dosing
- High-dose amoxicillin: 80-90 mg/kg/day in 2 divided doses 1, 2
- For your 13.43 kg child:
- 80 mg/kg/day = 1,074 mg/day (537 mg twice daily)
- 90 mg/kg/day = 1,209 mg/day (604 mg twice daily)
- Practical dosing: 600 mg twice daily
When to Use Amoxicillin-Clavulanate Instead
Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses) if the child has: 1
- Taken amoxicillin in the previous 30 days
- Concurrent purulent conjunctivitis (otitis-conjunctivitis syndrome)
- Moderate to severe illness
- Age younger than 2 years
- Attends daycare
- Recent antibiotic exposure (within 4 weeks)
For your 13.43 kg child, this would be approximately 600 mg amoxicillin/43 mg clavulanate twice daily.
Treatment Duration and Follow-Up
- Continue treatment for 10 days for children under 2 years or those with severe symptoms 1
- For children 2-5 years with mild-moderate symptoms: 7 days may be sufficient
- Treatment should continue for 48-72 hours beyond symptom resolution 2
Important Clinical Considerations
Why high-dose amoxicillin? The 80-90 mg/kg/day dosing (versus the older 40-45 mg/kg/day standard dose) achieves middle ear fluid concentrations adequate to overcome penicillin-resistant Streptococcus pneumoniae, which has altered penicillin-binding proteins 3. This high-dose regimen maintains efficacy against the most common AOM pathogens while remaining safe and well-tolerated 4.
Common pitfall to avoid: Do not underdose based on adult maximum doses. While some clinicians cap amoxicillin at 1,500 mg/day (the standard adult dose), the FDA-approved pediatric dosing of 80-90 mg/kg/day should be used regardless of whether it exceeds adult dosing 2, 5. For your 13.43 kg child, the calculated dose (1,075-1,209 mg/day) is well below this threshold.
Beta-lactamase producing organisms: Despite increasing prevalence of beta-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis (which are resistant to amoxicillin alone), recent evidence shows that treatment failure with amoxicillin monotherapy remains uncommon (approximately 5%) and does not significantly differ based on beta-lactamase production 6. This supports continued use of amoxicillin as first-line therapy for uncomplicated AOM.
Practical Administration
- Give with food to minimize gastrointestinal side effects 2
- Twice-daily dosing improves adherence compared to three-times-daily regimens 7
- If using oral suspension, shake well before each dose 2
- Refrigeration is preferable but not required; discard unused suspension after 14 days 2
When to Reassess
If symptoms worsen or fail to improve after 48-72 hours, consider switching to amoxicillin-clavulanate or a second-line agent such as ceftriaxone (50 mg/kg IM/IV for 1-3 days) 1.